Well actually
‘People should aim to get a variety’: the pros and cons of popular protein sources
Sarah Sloat
Tue 19 May 2026 18.00 CESTLast modified on Tue 19 May 2026 18.17 CEST
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https://www.theguardian.com/wellness/2026/may/19/pros-cons-popular-protein-sources
D o you think you’re not getting enough protein? Debbie Fetter, an associate professor in nutrition at the University of California, Davis, likes to ask her students this same question. In a lecture hall of more than 500 people, “almost every hand shoots up”, she says.
Protein is top of mind for consumers. A 2024 survey of 3,000 Americans suggests most are trying to eat more of it, and research shows that foods labeled “more protein” are especially appealing to consumers.
And as consumers become more aware of their intake, they may wonder whether some sources are better than others.
“People should aim to get a variety of protein sources in their diet,” says Andrea Glenn, an assistant professor of nutrition at New York University. Here’s how to navigate individual needs and preferences, while getting the nutrients needed for good health.
What is protein and why is it important?
Protein is essential for building and repairing tissues, and for making enzymes, hormones and disease-fighting antibodies. It is made up of smaller units called amino acids. The human body uses 20 amino acids to function; it can make 11, and the other nine must be obtained from food.
New US dietary guidelines recommend that adults consume 1.2-1.6g of protein per kilogram of body weight per day, up from the previous recommendation of 0.8 grams per kilogram of body weight per day – though some experts say the change is unnecessary and could lead to less balanced diets.
Trying to consume as much protein as possible doesn’t automatically result in more muscle or lean body mass, says Fetter.
Insufficient protein can cause muscle mass loss, anemia and slower metabolism. Overconsumption can put strain on the kidneys, says Nicole Stob, an assistant teaching professor of integrative physiology at the University of Colorado, Boulder.
Why is it important to think about protein sources?
“There’s a time and place for all proteins,” says Fetter. What’s best depends on the individual and their dietary needs and preferences.
One argument for eating a variety of proteins centers on nutrition. “Protein is important, but it’s not the only thing that’s important for health,” says Glenn.
Protein sources can provide essential nutrients like fiber, vitamins and minerals. Glenn emphasizes that it’s best to get protein from whole foods rather than ultra-processed foods.
The other argument is environmental. Plant proteins have a lower carbon footprint than animal proteins – particularly beef. A 2024 study found that eating red meat twice a week, compared with four times a week, can shrink your carbon footprint and increase longevity.
Beef
Protein content: Different cuts of beef can vary in protein content. For example, USDA data shows that 3oz of ground beef contains about 22.2g of protein, whereas 3oz of beef shank cross-cuts have about 28.6g.
Other nutritional benefits: Beef is a nutrient-dense , complete protein. A complete protein is one that supplies all of the amino acids the human body can’t make on its own. Meats and tofu are all complete proteins.
Some research suggests that eating moderate portions of lean beef as part of a healthy diet may not increase heart disease risk, while still providing protein, omega-3 fatty acids, vitamin B12, niacin, zinc and iron.
Cons: One of the primary concerns with beef is the potential high cholesterol and saturated fat content. The Cleveland Clinic notes that while there’s no official recommendation on how much red meat is fine to eat, sticking with smaller portions is probabaly best.
The American Heart Association encourages consumers to select beef products labeled “lean” or “extra lean”, which have lower fat, saturated fat and cholesterol content. By contrast, “prime” cuts contain more fat.
Pork
Protein content: One ounce of beef, chicken or pork contains about 7g of protein . The protein content of pork depends on how it is prepared. According to the USDA, ham contains 19g of protein per 100 grams, while pork chops contain 26.6g of protein per 100 grams.
Other nutritional benefits: Nutritionists describe fresh pork as a high-quality, low-cost protein. It’s also rich in B-complex vitamins and essential minerals like zinc and iron.
A 2025 study on intense exercise found that eating lean pork protein after training, compared with plant protein, can help with muscle soreness and inflammation, probably because pork contains more creatine and amino acids.
Cons: Some of the most popular pork varieties are processed meats like bacon and ham. Processed meats are linked to an increased risk of cardiovascular disease, cancer and type 2 diabetes. The World Health Organization describes processed meat as “probably carcinogenic to humans”.
Chicken
Protein content: Depending on the cut, cooked chicken can generally contain 23-31g of protein per 100g (3.5oz).
The protein amounts of chicken and other animal meats are comparable. For example, 100g of cooked sockeye salmon contains 26.5g of protein, while 100g of skinless, boneless chicken breast contains 29.5g of protein, and 100g of tenderloin steak contains 21g of protein.
Other nutritional benefits: A 2023 Purdue University study suggests that lean, unprocessed chicken is a healthy protein source, providing essential nutrients like potassium, iron and B-group vitamins.
Cons: The nutritional value of chicken can depend on how it’s prepared. While lean, unprocessed chicken is healthy, processed chicken may be high in sodium. Chicken skin can also be a source of saturated fat .
Fish
Protein content: Johns Hopkins Medicine data suggests 1oz of fish contains about 7g of protein. However, there are small differences among species. According to USDA data , one fillet of raw tilapia contains about 23.3g of protein, while one fillet of raw cod contains 17.7g.
Other nutritional benefits: Fish is a good source of omega-3 fatty acids, vitamin D, B12, iodine, selenium, potassium and lean protein. Compared with other animal meats, fish also tends to have less saturated fat . Adults should eat about two to three servings of fish per week because of all of the associated nutrients, according to the FDA and the American Heart Association .
Cons: “Fish is a good, reliable protein source,” says Stob. “The drawback with fish is the expense.” Canned fish can be cheaper than fresh.
Eggs
Protein content: One large, whole egg contains approximately 6.2g of protein, according to USDA data . Eggs contain about the same amount of protein whether or not they are cooked.
The egg yolk within a large egg contains about 2.7g of protein. The egg white of a large egg has about 3.6g of protein. Egg protein supports skeletal muscle health and can also decrease appetite.
Other nutritional benefits: Eggs are a nutrient-dense source of energy from protein, fat and several B vitamins. Eggs also contain vitamin E, iron, zinc and magnesium.
Egg whites are considered a “high-quality” protein because of their digestibility, protein content, and because they are low in fat, cholesterol and calories, Fetter says.
Cons: A large egg yolk can have about 186mg of cholesterol, which is why some experts recommend moderate to low egg consumption. But more recent research indicates that egg cholesterol levels don’t raise the risk of heart attack, stroke or other cardiovascular diseases. According to the Mayo Clinic , most people can eat up to seven eggs a week without affecting their heart health.
Beans
Protein content: Beans come in many varieties, and their protein amounts vary slightly, says Glenn. A half cup of kidney beans, for example, contains about 8g of protein ; the same amount of refried beans contains 6g.
Unlike animal protein, beans are incomplete proteins because they lack or are low in the amino acids people must get from food. However, combining them with grains creates a complete protein, says Stob.
Other nutritional benefits: Pulses (edible seeds from a legume plant, such as beans, lentils and peas) are healthy foods that can reduce the risk of conditions like heart disease, diabetes and some cancers.
Beans are more than just a source of protein. Garbanzo beans, for example, are a great source of minerals, B vitamins, carbohydrates and fiber. Beans’ high fiber content is particularly helpful: fiber is linked to lowering cholesterol and blood sugar, preventing constipation and managing weight.
“Compared to some animal sources, beans may contain a little bit less protein,” says Glenn. “But at the same time, you’re also getting fiber, which most Americans are not getting enough of.”
Glenn’s research suggests that substituting red and processed meat with plant proteins can yield cardiovascular benefits. A different 2021 study found that a plant-centered, high-quality diet starting in young adulthood is associated with a lower risk of cardiovascular disease by middle age.
“What we see from the evidence is that people who opt to make most of their protein sources come from plants have improved health outcomes and body composition,” says Fetter.
Cons: For people unused to fiber-rich foods , beans may cause gastrointestinal symptoms like bloating and gas. Add fiber to your diet gradually to help your body adjust.
Lentils
Protein content: A half cup of lentils contains about 9g of protein.
Other nutritional benefits: Lentils are a source of manganese, potassium, iron, fiber and folate.
Like beans , lentils contain plant chemicals called polyphenols that have antioxidant benefits and are linked to reduced blood pressure. They are also lower in calories than animal proteins and don’t contain saturated fat.
Scientists have found a link between eating lentils and a reduced incidence of diabetes, obesity, certain tumors and cardiovascular diseases. Some research suggests eating lentils can increase fullness and support weight management .
Glenn recommends using lentils in dishes like meatloaf and spaghetti bolognese. Cooking methods can alter some nutrient content – boiling, for example, can cause vitamin loss – but proteins typically stay intact regardless of how you prepare your meal, she says.
Because lentils are also incomplete proteins, Stob recommends alternating them with other protein sources, such as tofu.
Other advantages include affordability and a long shelf life.
Cons: As with other fiber-rich options, eating lentils can lead to digestive issues like gas and bloating.
Tofu
Protein content: The protein content of tofu varies by firmness and brand; for instance, some “super firm” varieties list higher protein counts than softer varieties. On average, a half cup of firm tofu contains roughly 21.8g of protein . Soy protein is a complete protein.
Generally, tofu has more protein per calorie and slightly more protein per serving than most cooked beans. For example, one cup of boiled black beans contains about 15.2g of protein.
Other nutritional benefits: Soy-based foods, including tofu, are rich in B vitamins, fiber, potassium, magnesium and protein.
When calcium sulfate is used as a coagulant in tofu, it becomes a good source of calcium. Tofu also contains natural plant compounds, including isoflavones , which are structurally similar to estrogen. A 2020 study found that higher intake of isoflavones and tofu was associated with a moderately lower risk of coronary heart disease. Other research suggests tofu consumption is associated with a lower risk of osteoporosis and breast cancer .
Tofu is higher in fat than other plant proteins like lentils or beans, but it contains heart-healthy polyunsaturated fat. Softer tofu has less fat than firmer varieties.
Cons: Soybeans are the main component of tofu. People who are allergic to soy should not eat tofu.
Protein powders
Protein content: Protein powders are made from different sources of protein, including whey, egg and pea. A serving of protein powder contains about 20-25g of protein , according to the Mayo Clinic.
The FDA does not regulate dietary supplements, including protein powders. It’s possible that the ingredients listed on the label are not in the product. Fetter recommends choosing products that have been through third-party testing .
Protein powders are primarily designed to supplement a diet, rather than replace foods. “I encourage people to get some whole food sources in there, and not just rely on protein powders or shakes for their protein sources,” says Glenn.
Protein powders are an effective source of protein, but if you opt for plant-based powders, seek varieties that combine multiple sources to ensure you get all the essential amino acids, Stob says.
Other nutritional benefits: Vitamins and minerals, such as potassium and calcium, may be included in protein powders, but researchers caution that there may be differences between what a label suggests and what the product actually provides.
Cons: Excess protein does not automatically translate into more muscle and can lead to excess calories . Some protein powders may be high in sugar and calories due to additives such as flavors and fillers. Glenn recommends avoiding protein powders with high levels of these additives; they are low-cost ingredients added to improve texture, but they dilute the protein content.
There’s a risk of lead exposure with some protein powders . However, there is probably no immediate harm associated with these levels of exposure.
